Find area of an irregular shape?

Answer 1

If you can find the perimeter, then you can find the area. Calculate the perimeter. Then times the top sides by the left and right sides (and obviously the bottom!) the there you have it. The area of an irregular shape!

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Total nonsense!

The above applies only to a square or rectangle - and a square in not even an irregular shape!

There are three main methods:

Method 1: The simplest situation is one in which the irregular shape can be divided up into shapes whose areas can be calculated. For example, the outline of an ice-cream cone may be viewed as a triangle with a semi-circle on top. So calculate the areas for the bits and add them up.

Method 2: Trace the shape onto dense lamina of uniform thickness. Cut out the shape and measure its mass. Next cut out a UNIT square of the same lamina and measure its mass.

Then

Area of irregular shape = Mass of irregular lamina/Mass of lamina square.

Method 3: Trace the shape onto a sheet of paper with square gridlines on it. Count the number of whole (or almost whole) squares inside the shape = A. Count the number of squares where approximately half is inside the area = B. Ignore all squares where only a tiny bit is in the marked area.

Then,

Area of irregular shape = (A+B/2)*area of unit square in the grid.

The finer the grid, the more accurate your result, but also the harder you'll have to work.